1. Field of the Invention
The invention relates to a cooking panel whose cooking units are heated with gas burners which are covered by a common or continuous cooking surface, consisting of glass ceramic or similar material.
2. Description of the Prior Art
Gas-fired cooking panels having a continuous cooking surface of glass ceramic or similar material are known. They are disclosed, for example, in the German Pat. Nos. 24 40 701, 27 21 921, 26 33 849 as well as in the French Pat. Nos. 2 058 722 and 2 076 174. The cooking units of these known cooking panels are heated with radiant gas burners according, for example, to the German Pat. Nos. 26 33 849 or with atmospheric burners. Differences between the embodiments according to the aforementioned patents consist, among other things, in the manner of managing the combustion air and the exhaust gas, this being done with auxiliary blowers in some of the devices--that, for instance, according to the German Pat. No. 20 76 174.
The fundamental structure of known cooking appliances of the type described above shall be described below with reference to the example of a cooking panel comprising a continuous cooking surface of glass ceramic heated with radiant gas burners that is equipped with three cooking zones and one warmer zone.
Each cooking zone of this cooking panel has a radiant gas burner allocated to it, the burner consisting of a gas mixing chamber with an externally attached venturi tube with a gas jet and a perforated ceramic plate which upwardly terminates the gas mixing chamber. The German Pat. No. 26 33 849 describes this type of burner. In operation, this ceramic plate is caused to glow by means of small flames that burn at the end of the perforation and functions as a heat radiator. A sheet metal ring, referred to as the exhaust gas ring, is put in place on this burner arrangement as a combustion chamber limitation, the ring being supported on a plurality of springs secured to the combustion chamber and being pressed by the springs against the glass ceramic cooking surface from below via a sealing ring consisting of refractory material. The exhaust gas ring carries a rod expansion switch for temperature limitation of the burner and the required ignition and monitoring electrodes as well as an exhaust gas nozzle. The latter discharges into an exhaust gas channel consisting of sheet metal which eliminates the burner exhaust into the warmer zone or directly out of the cavity. The warmer zone is heated by the exhaust gases of one or more cooking unit burners. It consists of an upwardly open sheet metal trough comprising a sealing ring and connections for the exhaust gas ducts as well as an exhaust stack. It is likewise pressed against the cooking surface by means of springs and conducts the exhaust gases into the open air via a system of baffle plates which serve the purpose of intimately mixing the hot exhaust gases with the cool ambient air.
All three cooking unit burners are completely independent of one another and consist of the above-described main components in addition to further piece parts.
The cooking unit burners are controlled with allocated solenoid valves that are disposed in the cavity space in the course of the gas conduits. A separate, thermally insulated housing is provided for the temperature-sensitive control and monitoring electronics, the housing being attached laterally or to the front of the cooking panel or being externally mounted at some other location.
The various, known cooking panels of the type described above are respectively constructed of similar component parts having equivalent functions and include a number of disadvantages:
The separate manufacture of the numerous, sometimes complex components as piece parts is cost-intensive and the assembly of the cooking panel necessarily requires a great assembly outlay with high assembly cost. The multitude of components promotes susceptibility to malfunction and reduces the service friendliness of these cooking panels. Also disadvantageous are the high weight of these cooking panels as well as the lack of versatility in the selection of the cooking unit diameters and the disposition of the cooking zones in the cooking surface. It is also disadvantageous that the individual burners have large structural heights, wherewith large overall heights of the cooking panels necessarily follow, in turn preventing easy incorporation of these cooking panels in kitchen appliances. A further disadvantage of the known cooking panels with gas firing and a continuous cooking surface is that the exhaust-carrying parts of sheet metal become very hot during operation and thus heat the cavity space surrounding the burner unit, so that electrical lines and auxiliary elements such as, for example, gas control valves that are disposed in the cavity space are exposed to great temperature stresses.
A further disadvantage given the known cooking panels is that the electrical ignition and flame monitoring require complex electronic control devices that are cost-intensive and which, due to their temperature sensitivity can only be disposed in spaces that are well thermally insulated, usually outside of the cavity space.